Background: TGF-beta type II receptor is considered as one of the tumor suppressor genes, and altered expression of TGF-beta RII has been found in many kinds of cancers.
Materials and methods: Seven NSCLC cell lines and 21 surgically resected NSCLC tissues were obtained. The growth inhibition by TGF-beta 1 was examined by MTT assay. Northern blot and Southern blot analysis were performed for TGF-beta 1 and TGF-beta RII in NSCLC cell lines. TGF-beta 1 and TGF-beta RII expression were analyzed by immunohistochemistry (IHC) in 21 surgically resected NSCLC tissues.
Results: Six of 7 NSCLC cell lines were resistant to TGF-beta 1. Southern blot analysis for TGF-beta 1 and TGF-beta RII showed no genetic changes. However, mRNAs of TGF-beta RII were barely detectable in 3 of 7 cell lines, and mRNAs of TGF-beta 1 were almost undetectable in 2 of 7. IHC revealed decreased TGF-beta RII expression in 6 of 21 surgically resected NSCLC tissues (5 adenocarcinomas, 1 sarcomatoid carcinoma). Being analyzed by the histologic subtypes, TGF-beta RII decreased in 5 of 8 adenocarcinomas but in only 1 of 13 non-adenocarcinomas (p = 0.0139). On the other hand, TGF-beta 1 was expressed at a higher level in 20 of 21 tumors.
Conclusion: These results suggest that decreased TGF-beta RII expression may play a role in human lung carcinogenesis, especially in adenocarcinoma.